我想出了一种将数字格式化为科学计数法的方法，我如何在需要时调用这个 function？

Question

I just started learning js and so far am making good progress. I have encountered an issue tho, and the title should basically tell you everything you need to know, but here goes anyways.

For the project I want to realize eventually, I'll need rather big numbers. So I came up with the following to format them to scientific notation:

<script>

    var rawNumber = 172 ** 25;          // The number that shall be formatted into scientific notation
    var exponentDisplay = "e+";         // Self explainatory
    var numberRelevantDigits = 0;       // The digits displayed before the "e+"
    var numberExponent = 0;             // Self explainatory
    var formattedNumberDisplay = 0;     // What will be displayed
    
    
    function formatNumber() {                                                                   // The function triggered by clicking the button
        var numberExponent = Math.floor( Math.log(rawNumber) / Math.log(10) );                  // Calculating the exponent of the number in scientific notation
        var numberRelevantDigits = rawNumber / 10 ** numberExponent;                            // Dividing the number by 10 to the power of its exponent
        var numberRelevantDigits = numberRelevantDigits.toFixed(3);                             // Rounds the relevant digits to 3 decimals
        var formattedNumberDisplay = numberRelevantDigits + exponentDisplay + numberExponent;   // Adding the relevant digits, "e+" and the exponent into a string
        document.getElementById("formattedNumberDisplay").innerHTML = formattedNumberDisplay;   // Changing the display to the formatted number
        }
        
</script>

This works as intended, but I don't want to put this chunk of code whenever I need a number formatted. Is there a way (or rather: which is the way) to make it so I can just call that function whenever I need a number formatted? Even if I need use different variables?

Let me apologize again, since this has likely been answered a dozen times before, but I don't even have a clue what to even look for.

Thank y'all in advance.

Answer 1

• Create a js file and import it whenever you want
• also you should pass the variables to the functions instead of declaring them as a var
• inside funciton use const and let, you might some ugly bugs in the future if you don't.

Your file NumberFormater.js will look like:

 export formatNumber = (
       rawNumber,
       exponentDisplay,
       numberRelevantDigits,
       numberExponent,
       formattedNumberDisplay    
      ) => {
        let numberExponent = Math.floor( Math.log(rawNumber) / Math.log(10) );                  // Calculating the exponent of the number in scientific notation
        let numberRelevantDigits = rawNumber / 10 ** numberExponent;                            // Dividing the number by 10 to the power of its exponent
        let numberRelevantDigits = numberRelevantDigits.toFixed(3);                             // Rounds the relevant digits to 3 decimals
        let formattedNumberDisplay = numberRelevantDigits + exponentDisplay + numberExponent;   // Adding the relevant digits, "e+" and the exponent into a string
        document.getElementById("formattedNumberDisplay").innerHTML = formattedNumberDisplay;   // Changing the display to the formatted number

      }

then when needed:

 import { formatNumber } from './NumberFormater.js';
 const rawNumber = 172 ** 25;          // The number that shall be formatted into scientific notation
 const exponentDisplay = "e+";         // Self explainatory
 const numberRelevantDigits = 0;       // The digits displayed before the "e+"
 const numberExponent = 0;             // Self explainatory
 const formattedNumberDisplay = 0;     // What will be displayed

 formatNumber( rawNumber, exponentDisplay, numberRelevantDigits, numberExponent, formattedNumberDisplay);

read more on js modules https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules Hope I've helped.